Use intelligent natural language understanding instead of hardcoded keywords

Fix: Better handling of natural language exit signals

Clean up and simplify system

docs: Major cleanup and reorganization

feat(agent-briefing): Add intelligent agent-driven daily briefing system

Add conversation history persistence, intelligent fallback, and enhanced features

Add automated daily morning briefing feature

Update documentation with latest chat interface improvements

Disable automatic label generation during task polishing

Add support for numbered list task identifiers and improve multi-word matching

Fix task identification in _identify_tasks_for_polish to try name matching before fallback

Improve intent routing for polish commands with clearer function descriptions

Fix OpenAI function routing confusion between polish_tasks and polish_and_apply

Update README to reflect OpenAI migration

Update documentation for enhanced chat interface